President Barack Obama says the death of former Libyan leader Moammar Gadhafi ends what he calls a long and painful chapter, after decades of rule by an iron fist. Officials say the president was briefed early Thursday about Gadhafi’s death.

President Obama said he is very proud of the NATO alliance’s work in Libya, and of the Libyan people’s efforts to topple their longtime leader.

In a White House meeting, the president thanked Norway’s prime minister, Jens Stoltenberg, for his country’s contributions to the NATO mission in Libya, and stressed the importance of international cooperation.

“We were proud of the leadership we showed in that process, but increasingly, wherever we have the possibility of working with outstanding partners like Norway, then I think that we are going to be even more effective,” Obama said.

Earlier Thursday, White House spokesman Jay Carney said the killing of Gadhafi will end the NATO mission in Libya, which started in March to protect Libyan civilians from Gadhafi’s forces.

“Not just because of the announcement of Gadhafi’s death, but because of the successful taking of Sirte and other areas, most of Libya is now under control of rebel forces, under control of the TNC,” Carney said.

Carney said the Transitional National Council, which is governing Libya, is the only authority which is claiming to be in charge.

Mr. Obama’s spokesman echoed the president’s call for the TNC to build a democratic government as quickly as possible. He said the group has consistently promised to do so.

“It has been a number of months since we recognized the TNC, and we have, even prior to that, been engaged diplomatically with the TNC, as have our allies. So we have a good feeling for and understanding of that body, and we would simply point you to the statements that they have made about their commitment to a democratic transition in Libya,” Carney said.

Carney said the United States will work with other countries to assist Libya in its transition to democracy. He did not specify how that would be done.

He also said Washington is calling on Libya’s leaders to consolidate military forces under civilian control and work to control dangerous materials.

The White House spokesman indicated that U.S. military intervention in Syria, to drive out that country’s president, Bashar al-Assad, is not likely. But he said the movement called the “Arab Spring” will likely touch Syria as well.

“The events of this entire year in that region of the world have spoken more dramatically than any individual could about where the future lies in that region. And it is a future that lies with the youth of the region and those who are demanding greater democracy, greater accountability from their governments, greater freedom. That is as true in Syria as it is in Libya,” Carney said.

Carney said the president was informed about Gadhafi’s death at his daily security briefing Thursday, but was aware of reports about the event earlier in the day.